Thermal Behavior and Crystallization of $Fe_{81 - x}Co_{x}Zr_7Nb_2B_{10}$ (x = 2, 4, 6) Alloys

Thermal behavior and microstructure of $Fe_{81 - x}Co_{x}Zr_7Nb_2B_{10}$ (x = 2, 4, 6) alloys were investigated by differential thermal analysis and X-ray diffraction. Both the supercooled liguid region Δ $T_{x}$ and the first crystallization peak temperature $T_{p1}$ are the lowest and the span Δ $T_{p}$ between $T_{p1}$ and $T_{p2}$ is the highest when 4 at.% Fe is substituted by Co. The crystallization activation energy $E_{p1}$ for $Fe_{75}Co_6Zr_7Nb_2B_{10}$ alloy is the minimum for the heating rates ν = 5-20 K/min. $E_{p1}$ for $Fe_{77}Co_4Zr_7Nb_2B_{10}$ alloy is the minimum for the heating rates ν = 20 - 50 K/min. The crystallization processes of $Fe_{81 - x}Co_{x}Zr_7Nb_2B_{10}$ (x = 2, 4, 6) amorphous alloys are similar on the whole, which is as follows: amorphous → amorphous + α-Fe(Co) → α-Fe(Co) + $Fe_3Zr$ + $Fe_2Nb_{0.4}Zr_{0.6}$.